The present disclosure generally relates to paper products, and more particularly, to paper products comprising polylactic acid.
Paper, paperboard and other fibrous sheets made from natural cellulose-based fibers are biodegradable. However, fibrous sheets tend to be porous. As a result, they do not provide good barriers against liquids. When fibrous sheets are used in applications where they will be exposed to liquids, they must generally be treated with a liquid-resistant material, such as paraffin wax or plastic. By doing so, however, the fibrous sheets are no longer biodegradable, but are as resistant to degradation as plastic or paraffin wax.
Recently, due to increased environmental awareness, much attention has been directed toward polymers such as polylactic acid (PLA) that are biodegradable. Polylactic acid is a thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch or sugarcanes.
The use of polylactic acid in paper products, however, has been limited due to at least the cost disadvantages of polylactic acid. In general, the cost of polylactic acid is double that of petroleum based materials. To compound matters, polylactic acid has a higher density than petroleum based materials, which requires the use of more polylactic acid per pound as compared to petroleum based materials. Due to at least these complicating factors, polylactic acid has not readily been adopted for use in paper products.
Accordingly, a continual need exists for improvements in the use of polylactic acid with paper products.